This talk concentrates on the procedural contributions Vesalius made in his 1543 De humani corporis fabrica. Vesalius began his medical studies at the University of Paris, which was still a conservative institution that relied heavily on readings from Galen and later Medieval summaries and re-quired little or no hands-on dissection, even of an-imals. Vesalius introduced a new regimen at the University of Padua that called for hands-on dis-section by the students themselves and visual test-ing of anatomy rather than dependence upon books. He relied upon a tag from Horace, "Given to swear by the words of no man" which later be-came the motto of the Royal Society.